People who refrain from eating any meat or animal products could be putting their heart health at risk.
Research published in the Journal of Agricultural and Food Chemistry found that a strict vegan lifestyle can result in an increased risk of developing blood clots and atherosclerosis – or the hardening of the arteries.
These conditions are known to increase the risk of heart attacks and stroke.
Key nutrients were found to be lacking in the vegan diet that had an affect on heart health.
These include iron, zinc, vitamin B12 and omega 3 fatty acids. However, some of these can be found in non-animal foods, for example, walnuts are high in omega-3.
Dui Li, who worked on the research, said that the conclusions did not stretch to vegetarians.
It is thought that their lower intake of fat from meat contributes towards a lower risk of cardiovascular problems among vegetarians than meat eaters.